Time delay program relay



y 8; 1956 A. L. JUDSON ETAL 2,744,573

TIME DELAY PROGRAM RELAY Filed Feb. 15, 1954 2 Sheets-Sheet l 2 Z :::I'I:

INVENTOR. A/ber/ L. Judson By Rober/ f. Lac/2 W y 8, 1956 A. L. JUDSONEI'AL 2,744,573

TIME DELAY PROGRAM RELAY Filed Feb. 15, 1954 2 Sheets-Sheet 2 INVENTOR.A/ber/ L. Judson Ruben Zach United States Patent TIME DELAY PROGRAMRELAY Albert L. Judsonaand Robert E. Lach, Portland, 0reg., assignors.to Iron- Fireman Manufacturing Company, incorporation of OregonApplication February 15, 1954, Serial No. 410,165 4 Claims. (Cl. 1611)This invention relates generally to electrical relays and moreparticularly to relays adapted-to delay the relayed' signal inproportion to another time variable.

Specifically the'relay of this invention is adapted to delay theapplication of the plate voltage to an electronictube for a sufficienttime after the beginning of hcating of the cathode element for theelements of the tube" to attain their'respective desired startingtemperatures'.

It should'be understood that this is not the first relay which'has beendeveloped and provided for this purpose since others, more complicatedand more expensive, have been used.

It is'therefore a principal object of this invention to provide such arelay of great simplicity relative to its required function.

A relay for the stated purpose has two timingfunctions; The first of itsfunctions is to close the 1oad,.or plate voltage applying switch, afixed time after receipt ofia starting signal if the electronic tube iscold. The second of its functions is variably to delay the closing ofthe load switch after an interruption of power supplied to the tube.

Specifically the program required of. the present invention is to closeits load switch in three minutes and fifty-five seconds after power isfirst applied to the tubes cathode heater. Then, if there is aninterruption of power to the tube of less than eight and. one-halfseconds, to maintain the load switch. closed. If the power interruptionlasts eight and one-half seconds, the relay is required to open its loadswitch and maintain the load switch open for a minimum time of oneminute.- Should the power interruption last longer than eight andonehalfseconds and. variably up to a total of six minutes, the relay isrequired to delay the reclosing of its load switch for one minute plusone-half the amount of time over eight and one-half seconds duringwhich. the power interruption lasts.

It isa second object of this invention tov provide such a relay having.the. stated program characteristic, itbeing.

understood thatthe proportions-of parts and selection of elements may besuch as to give any similar program desired.

The novel and useful elements and arrangements discovered and inventedjointly by us for the present purpose and. to which we lay claim forthese and all analogous. uses are described'in the following'explanationre-' ferring to the attached drawing in which- Fig. lis a viewof ourrelay in side elevation.

Fig. 2 is a sectional view of our relay along the line 2-2' of Fig. 1.

Fig. 3 is a fragmentary plan view along'the line 3-3' Fig.4 is afragment of the sectional view of Fig. 2 taken along the line 4-4 ofFig. 3.

Fig. 5 is similar to Fig; 4 with the cycle'further advanced.

Fig. 6 is similar. to. Fig. 5 with the cycle still further advanced.

Like numerals of reference refer to like parts in the several figures ofthe drawing.

It should also be noted that in each of the figures of the drawing partshave been omitted for the purpose of better disclosure of the remainingparts and their interaction.

As shown in the drawing our relay comprises a base plate 11 on which aresecured upright bearingplates 12 and 13 by screws 14 and 15respectively. Cam shaft 16 journalled in plates 12 and 13 is coupled bycoupling 17 to rotor shaft 18 of spring motor 19 having feet 20 securedto base 11 by screws 21. Synchronous timing motor 22 secured to plate13'by screws 23 through motor case ears 24 has secured to its outputshaft 25 drive pinion 26 permanently meshing with gear 27 havinghub 28freely rotatably supported on shaft 16. Also freely rotatably supportedon shaft 16 is hub 35 of gear 29 permanently meshed with pinion 30secured to pinion 31 with both pinions 30 and 31 freely rotatablysupported on pinionshaft 32 journalled in toggle lever clip 33 andguided formotion radial to shaft 16 in slots 34 in plates 12 and 13.

Timing cam 36 having hub 37 secured on shaft 16 is perforatedwitharctuate slot 38 adapted to receive cam drive pin 39 secured to gear 29.The angular length of slot 38 and the diameter of pin 39 are selected toallow a maximum angular movement ofgear 29 with respect to cam 36 offifty-five and three-quarters degrees. Spring 40 biases pin 39 and gear29 toward clockwise movement relative tocam 36 as viewed in Figs. 2, 4,5 and 6.

U-sectioned' toggle lever arm 41 having back plate 42 and bottom plate45 is freely rotatably supported at one endon pin 43 secured in plates12 and 13 and its other end is hinged. by pin 44 to toggle lever clip33. Tension spring 46 secured between bottom plate 45 of toggle lever 41and stationary pin 47 secured to plate 12 biases toggle lever. 41towards counter-clockwise movement as seen in Fig. 2. Stop 48 secured toplate 13 by screws 49 limits the clockwise movement of lever 41.

Electromagnetic operator 50 secured to plate 13 has magneticallyoperatedarmature 51 (see Fig. I) extending' laterally across and restingagainst back plate 42 of toggle lever 41. Armature 51 is guided as shownin notch 52 in plate 13. Clip 53 secured to plate 12 by screw 54limits.the release movement of armature 51 and thus-limits. thecounterclockwise movement of-toggle lever 41 under the bias of spring46. When operator 50 is energized through wires 53a and 54 from directcurrent source 55'by the closing of starting switch 56 armature 51 movesinwardly pressing toggle lever 41 with'it against the bias of spring 46and moves pin 44 upward causing pinions 30, 31 on pin 32 guided in slots34 to move radially. toward gears 29 and 27 respectively and causingpinion 31 to mesh with gear 27. It should be emphasized that pinion 31.and gear 27 have relatively small and therefore radially short, teethwhile pinion 30 and gear 29 have relatively large, and thereforeradially longer, teeth. Thus when operator 50 is deenergized and togglelever 41 is moved counterclockwise by spring 46 until stopped by clip53, pinion 31 is out of mesh with gear 27 but pinion 30. remains meshedwith gear 29 at all times. Therefore when. operator 50 is deenergizedpinions 31, 30' and gear 29 are free of control by gear 27, but whenoperator 50 is energized gears 27 and 29 are coupled through pinions 30,31 and if motor 22 is energized through. wires 57, 58 and switch 60 fromelectric power source 59, gear. 29 is driven by. motor 22 through pinion26, gear 27, pinion 31 and pinion 30. motor 22 is selected to drivepinion 26 at 2 R. P. M.,

Since:

sincethe tooth ratio of pinion 26 to pinion 31 is 1 to 2 and since thetooth ratio of pinion to gear 29 is 1 to 6, gear 29 will be driven bymotor 22 at a constant rate of one-sixth R. P. M. or an angular rate ofone degree per second in a counterclockwise direction as seen in Figs.2, 4, 5 and 6.

Switch 60 is seen to comprise a pair of terminal straps 61, 62insulatedly secured by rivets 63, 64 between insulation blocks 65, 66 tobracket 67 secured to plate 13 by rivets 68. Secured at one end toterminal strap 61 is resilient switch blade 69 carrying movable contact70 biased by blade 69 towards stationary contact 71 carried by terminalstrap 62.

Spring actuated motor 19 is a common type of spring actuated timerequipped with an escapement mechanism to drive cam shaft 16 at acoratant rate of one-twelfth R. P. M. in a clockwise direction as viewedin Figs. 2, 4, 5 and 6. Since drive pin 39 is secured at one end to gear29 and is adapted to engage cam 36 with the other end of pin 39 in slot38 of cam 36 it is seen that when electric motor 22 is energized it candrive shaft 16 through pin 39 and cam 36 in a counterclockwise directionat a rate of one-sixth R. P. M. and wind the actuating spring of springmotor 19, but if motor 22 is dis engaged from gear 29 by thedeenergization of operator motor 19 will drive shaft 16 and cam 36 in aclockwise direction at a rate of one-twelfth R. P. M. The drive of cam36 by motor 22 is limited by the opening of switch by the engagement ofthe free end of switch blade 69 by insulating disk 72 secured by rivet73 to bracket 74 secured to gear 29 by rivet 75. See Fig. 6. The driveof cam 36 by motor 19 is limited by the abutment of radial edge 76 ofcam 36 with stop bracket 77 secured to plate 12 by rivets 78.

Pivotally carried on cam 36 by pivot pin is latch lever 80 formed'withlatch 81 at one end and carrying roller 82 on pin 83 at its other end.,Compression spring 84 secured at one end to cam 36 and at its other endto lever 80 near pin 83 biases lever 80 towards clockwise rotation aboutpin 79 which motion is limited either by lever 80 striking drive pin 39or stop pin 85.

With drive pin 39 (see Figs. 2 and 3) biased by spring 40 towards theend of slot in which it .is shown in Figs. 2 and 3 and with cam 36against 77 which limits its clockwise motion, with motor 22 energizedand operator 50 deenergized, the mechanism is ready to begin a timingcycle when operator 50 is energized and motor 22 is coupled to shaft 16as previously explained. Gear 29 and drive pin 39 travelcounterclockwise with cam 36 held sta- L tionary against stop 77 byspring motor 19. Overcoming 4 of fifty-five and three-fourths secondsuntil it strikes the forward end of slot 38 and then carries cam 36 withit until load switch S5 is closed and motor switch 60 is opened. Themechanism of load switch 85 will now be explained.

Bracket 86is secured by screws 87 to insulating plate 88 secured toplate 13 by screws 89. Resilient switch blade 90 carrying movablecontact 91 of switch 85 is secured at one end to bracket 86 and isbiased at its other or free end towards contact of contact 91 withstationary contact 92 carried on bracket 93 secured by rivets 94 toinsulating plate 95 secured to plate 12 by screws 96. Load circuit wires97, 98 are secured to switch terminal brackets 93 and 86 respectively byscrews 99 and 100.

Bell crank 101 is formed with vertical pivot slot 102 adapted to receivepivot pin 103 fixed to plate 12. Spring 104 secured at one end to bellcrank 101 and at the other to stud 105 secured to plate 12 biases bellcrank 101 downwardly and counterclockwise as viewed in Fig. 2. Nylon camrider 106 is secured by rivets 107 to the upper end of bell crank 10].Flange 108 formed on the lower free end A of hell crank has its upwardmotion limited by screw 109 threaded into lip 110 punched from and partof plate 12. Contacts 91 and 92 of switch 85 are opened against the biasof blade 90 by upward motion of nylon disk 113 secured to the lower legof bell crank 101 by rivet 111.

The operation of load switch 85 is as follows. Follow ing the start ofthe timing period as above explained pin 39 travels for fifty-five andthree-fourths seconds .in slot 38 and then picks up cam 36 and continuesto run counterclockwise. When cam 36 has progressed for seconds pin 39has been travelling 230 and three-fourths seconds and forward edge 112of cam 36 strikes the under side of cam follower 106 which is carriedupward against the bias of spring 104. At this time slot 102 raisesalong pin 103 further opening switch 85 as bell crank flange 108 pivotson screw 109 and bell crank 101 pivots clockwise. After an additionaltravel of cam 36 of four and one-quarter seconds or a total travel ofpin 39 of three minutes and fifty-five seconds bell crank 101 has movedclockwise sufiiciently for cam follower 106 to slide off the radial edge112 of cam 36 and due to the bias of spring 104 bell crank 101 slidesvertically downward guided by pin 103 in slot 102 and cam follower 106resting against the arcuate outer edge of cam 36. Disk 113 falls withbell crank 101 and due to the bias of blade 90 contacts 91, 92 of switch85 close. It is thus seen that our relay times out a delay of threeminutes and fifty-five seconds after operator 50 is energized beforeload switch 85 is closed, and immediately after load switch 85 is closeddisk 72 carried by gear 29 on bracket 74 strikes blade 69 of switch 60and opens the circuit of motor 22 to halt the progress of shaft 16 andcam 36.

Once a communication system is operating it .is important that it keepoperating as scheduled. However, power interruptions will occur and whenthey do occur it is important to resume operation as soon as possibleafter power is restored. In the particular system for which the form ofour relay here typically shown is adapted for the purpose of applyingplate voltage to an electronic tube only after the tube is thermallystabilized it has been found that for a power interruption of up toeight and one-half seconds voltage can be restored to the plate circuitimme diately on the restoration of power. Therefore on a powerinterruption of up to eight and one-half seconds voltage can be restoredto the plate circuit immediately on the restoration of power. Thereforeon a power interruption signalled by the deenergization of our operator50 our load switch 85 will not open for eight and one-half seconds. Ifthe power interruption lasts eight and one-half seconds the tube shouldbe heated for one minute before voltage is restored to the platecircuit. If the power interruption lasts longer than eight and one-halfseconds the tube should be heated for one minute plus one-half the time.in excess of eight and one-half seconds that the power interruptionlasts. And finally if the power interruption extends for six minutes itis assumed that the tube is cold and the full heating delay of threeminutes and fifty-five seconds is required before plate voltage isapplied. As above noted power interruption to the system is evidenced atour relay by the deenergization of operator 50. Plate voltage to thetube is applied on closure of load switch V toggle arm 41 dropsreleasing pinion 31 from mesh with gear 27, gear 29 is free to rotate onshaft16 except for its restraint by latch 81 on pin 39 and the bias ofspring 40. Also shaft 16 with cam 36 is relieved of the restraint ofmotor 22 and starts to rotate clockwise at a constant rate ofone-twelfth R. P. M. under the influence of the unwinding force ofspring motor 19.

Remembering that motor 22 is adapted to drive shaft 16 counterclockwiseat one-sixth R. P. M. and that motor 19 is adapted to drive shaft 16clockwise at one-twelfth R. P. M. it is seen that for the same angulartravel cam 36 takes twice the time to move clockwise ascounterclockwise. Therefore it is seen that it will take eight andone-half seconds time of clockwise travel (timed power interruption)with load switch S closed for cam 36 to move from the position shown inFig. 6 for radial edge 112 of cam 36 to move downward sufficiently forthe lower edge of cam follower 106 to move thereover under the influenceof spring 104.

As soon as gear 29 with cam 36 starts to move clockwise disk 72 movesaway from blade 69 which closes switch 60 so that motor 22 can takecharge of cam 36 immediately after power is restored. But if the powerinterruption lasts eight and one-half seconds as above noted cam 36moves away to allow spring 104 to rotate bell crank 101 counterclockwiseabout pin 103 until flange 108 strikes screw 109. This is sufiicientmovement of bell crank 101 for its lower leg carrying disk 113 to moveupward and open switch 85 and for its upper leg to move to the left withcam follower 106 sliding along cam edge 112 and striking roller 82 torotate latch lever 80 counterclockwise and release drive pin 39 fromlatch 81 as shown in Fig. 5. When latch 81 releases pin 39, spring 40moves pin 39 with gear 29 to the clockwise end of slot 38. Thereforeshould power be restored in eight and one-half seconds it will take themotor 22 one minute to reclose load switch 85 and reapply voltage to theplate circuit of the tube.

Should the power interruption last longer than eight and one-halfseconds cam 36 will continue to travel clockwise from the position shownin Fig. 5 an additional time which will be twice as long as the timerequired when power is restored for motor 22 to return cam 36 to theposition shown in Fig. 5. Should the power interruption last for sixminutes or more cam 36 will travel counterclockwise until stopped at itscold start position with edge 76 of cam 36 against stop 77.

Having thus recited some of the objects of our invention, illustratedand described one form in which our invention is practiced and explainedits operation, we claim:

1. In combination, a cam shaft, means supporting said shaft for rotationbetween limit positions in either direction, a cam secured on said camshaft to rotate therewith, a first rotational bias means connected withsaid shaft continuously to urge said shaft towards rotation at oneconstant speed in one direction towards one of said limit positions, asecond drive means, means for energizing said second drive meanscontinuously to rotate at another constant speed in the other direction,transmission means including a coupling means for coupling said seconddrive means to said cam shaft when said coupling means is energized todrive said cam in said other direction against the bias of saidrotational bias means, said transmission means including a lost motionmeans between said coupling means and said cam, energizing means forsaid coupling means, said lost motion means including a first resilientmeans providing a delay in the effectivity of said second drive means indriving said cam for a fixed time period when said coupling isenergized, said transmission means including latch means for said lostmotion means to incapacitate said resilient means at the end of saidfixed time period, stop means for limiting the rotation of said shaft insaid one direction, means for limiting the rotation of said shaft insaid other direction by said second drive means, a load switch,operating means operable by said cam at a first selected position whilesaid cam is being driven by said second drive means to close said loadswitch and at another position while said cam is being driven by saidfirst rotational bias means to open said load switch, said operatingmeans including a second resilient means for unlatching said latch meansto restore the effectiveness of said lost motion means when said loadswitch is opened.

2. The combination of claim 1 in which said lost motion means includesan arcuate slot formed through said cam concentric with said cam shaftand a drive pin parallel to said cam shaft and extending into said slot,said drive pin being rotated about said cam shaft by said second drivemeans from one end of said slot to the other end of said slot againstthe bias of said first biasing means when said coupling means isenergized.

3. The combination of claim 2 in which said latch means includes a leverpivotally secured to said cam for oscillation in a plane normal to saidcam shaft, said lever being formed with a latch hook thereonpositionable in the path of said drive pin and means for biasing saidlatch hook end of said lever towards said drive pin to engage said drivepin when said pin is positioned at the end of said slot towards which itis driven by said second drive means and hold said pin at said end ofsaid slot.

4. The combination of claim 3 in which said operating means for saidload switch operable at another position while said cam is being drivenby said first rotational bias means to open said load switch includesmeans associated with said cam at said another position to actuate saidlatch lever to release said drive pin from said latch hook and allowsaid first resilient means to rotate said drive pin with respect to saidcam to the end of said slot opposite the end in which it was latched.

References Cited in the file of this patent UNITED STATES PATENTS

